Thou Shalt...

• Mod to increase realism
• Create and use house mods that make sense in lore (or at least are not Disney Castles)
• Remember that thy character is the Dragonborn, not a king or queen, and that no one in the game seems to care about you

Thou Shalt Not...

• Use unrealistic hair colors unless it pertains to the personality AND preferences of thy character
• Use unrealistic skin colors unless it can be explained through lore
• Go overboard with the tats
• Use mods to make thyself godly, as changing the difficulty to "Novice" does exactly what you want
• Add additional races unless it can be explained through lore (aka no shinigami please)
• Go overboard with magic

Lastly, thou shalt not use the OP perks because the game should be challenging (haw haw, Skyrim? challenging?), and using those perks makes the game (too) laughably easy.